I used the tablet laptop for all my classes ranging from sophomore-level introductions to linear algebra (Math 221) and differential equations (Math 225) to special topics courses on numerical methods (Math 621) and parallel computing (Math 447 and Math 627). The effort started as part of the hybrid redesign of Math 221 in Summers 2006 and 2007, and support for this from the Office of Information Technology that funded the equipment. I remain indebted to John Fritz of DoIT, who told me about tablet laptops and their potential for freehand writing on a computer after some meeting of the Computer Policy Committee (CPC) of the Faculty Senate.
The software OneNote does not have any zoom feature, hence I had to buy the largest screen available for a tablet laptop in 2006, which was 14 inch. The problem is really that one has to write letters large enough to make them clearly readable, hence the need for the largest possible writing surface. In practice, this results in tension between the requirement for me to write large to make the writing legible and the desire to fit as much material on the screen at any given moment, since the audience sees only this material displayed by the projector. The upshot is that there was always less material visible at any given moment than would have been on a traditional chalkboard of typical classroom size. In the context of fairly complex mathematical formulas (like partial differential equations in graduate courses), I learned to expect only six lines of equations to be visible simultaneously.
There is also a funky problem with the display of a tablet vs. the output to a data projector via the VGA cable: While you can control the orientation of the screen, the orientation of the output to the data projector is fixed. So, for the projected display to be right-side-up, I was forced to physically rotate the tablet laptop on the lectern and adjust the screen orientation then accordingly. This makes you stand in front of the various cables that are supposed to be in the back of the laptop. To at least not bump into the VGA cable, Steven Anderson of AV Services helped me with a special cable that makes a right-angle connection.
During 2010, I studied what tablet laptops are available to replace the aging Toshiba from 2006. The basic fact is that screen sizes have gone down, with most only 12 inch. Fujitsu was the only company I could find with 13 inches. I tried out a loaner of this size, and I only got five lines of complex equations on the screen, as opposed to six on the old Toshiba. I conclude, we would be down to four with a 12 inch screen. Clearly, both of these are very problematic options. I also watched the developments around the Apple iPad, but it did not seem like a viable option at the time, also because of its inconsistencies in connecting to a projector. But in 2011, I became more familiar the Apple iPad2, thanks to our department chair Nagaraj Neerchal, and I found out about the application NoteTakerHD, as detailed in the follow-up webpage.